Composition containing unsaturated silicone compounds, dental materials containing them and use thereof

ABSTRACT

The invention relates to a curable composition comprising addition curable silicone component (A) having a linear siloxane backbone at least one unsaturated, non-activated side group pendant from the Si atom or atoms in the backbone, component (A) having an equivalent weight in the range of about 68 to about 1000, crosslinker component (B) comprising at least 2 SiH groups, catalyst component (C) being able to catalyse the reaction between component (A) and component (B), filler component (D), wherein the equivalent weight is defined as (molecular weight of the molecule)/(number of unsaturations in the molecule).

This application claims priority from European Application Serial No.04024243.0, filed Oct. 12, 2004.

The invention relates to a curable composition comprising an additioncurable component having a relatively high number of unsaturated sidegroups as well as to a method of producing this component. The componentand the composition comprising this component are especially useful forthe production of dental materials.

Hydrosilation as a mechanism of curing is used, e.g., in curablecompositions resulting in elastomeric three-dimensional shapes or incoatings. The materials in question usually show little mechanicalresistance and are either rubber-like or brittle. Formulations cured byhydrosilation are not likely to lead to three-dimensional shapes withmechanical resistance adequate for dental restoration, cements orprovisional crowns and bridge materials.

In U.S. Pat. No. 5,849,812 A1, an addition crosslinkable, polyetherimpression material is described that comprises an organopolysiloxanewith at least two alkenyl groups.

U.S. Pat. No. 6,335,413 B1 describes curable materials containing organohydrogen polysiloxane dendrimers with at least three SiH groups in themolecule, a catalyst, fillers and at least one silane dendrimer withterminal alkenyl groups. The patent indicates that the materialsobtained after curing have an increased hardness and a viscositysuitable for processing in the dental field. A Shore hardness D of thematerials after 24 hrs of 41 is reported. The patent indicates that thematerials can be used for bite registration, temporary and permanentfilling materials, crown and bridge materials as well as cements andvarnishes.

U.S. Pat. No. 6,313,190 B1 describes addition cross-linkable,two-component, silicone materials based on polysiloxane, wherein aftercross-linking via a hydrosilation reaction, the silicone materials havea Shore hardness D of greater than 35 and a modulus of elasticity ofgreater than 20 MPa. The patent indicates that these materials can beused for bite impressions.

All the aforementioned materials have disadvantages. For example, thematerials lack the desired combination of properties desired for dentalmaterials such as low viscosity before curing, and adequate hardnessafter curing. Therefore, there is a need for alternative compositions,especially for use in the dental field.

The invention relates to a curable composition comprising:

-   -   addition curable silicone component (A) having a linear siloxane        backbone, at least one unsaturated, non-activated side group        pendant from the Si atom or atoms in the backbone, component (A)        having an equivalent weight in the range of about 68 to about        1000;    -   crosslinker component (B) comprising at least 2 SiH groups;    -   catalyst component (C) able to catalyse a reaction between        component (A) and component (B); and    -   filler component (D),        wherein the equivalent weight is defined as (molecular weight of        the molecule/(number of unsaturations in the molecule), total        number of carbon-carbon double bonds in component (A) is at        least 3, and wherein the unsaturated, non-activated side group        does not comprise a —O—Si—CH═CH₂ moiety.

Some of the embodiments of the invention have improved properties, e.g.,high hardness after curing and some embodiments also have relatively lowviscosity before curing.

The terms “comprise” and “contain” within the meaning of the inventionintroduce a non exhaustive list of features. Likewise, the word “one” or“a” is to be understood in the sense of “at least one”.

The term “addition curable silicone component” refers to polymerscomprising alternating silicon and oxygen atoms (i.e., apolysiloxane-type chemical structure) and having sufficient pendantfunctional groups to undergo a setting reaction, preferably resulting ina completely cured material in the presence of a crosslinker compound ashereinafter defined and a catalyst material.

The term “crosslinker” refers to polymers that react with the functionalgroup or groups on other polymer chains to lengthen them and connectthem, e.g., to form a crosslinked network characteristic like that of acured silicone elastomer. In contrast to a thermoplastic polymer, (i.e.,a polymer that softens and flows upon heating) a crosslinked polymer,after crosslinking, is usually incapable of further flow. Cross-linkedpolymers differ in some important respects from linear and branchedpolymers. For example they swell in good solvents to form a gel but donot dissolve to form a solution. At elevated temperature, cross-linkedpolymers behave like soft but elastic solids rather than viscousliquids.

The term “hydrosilation” means the addition of an organosilicon hydridecompound to a compound containing an aliphatic multiple bond (e.g., anolefinic or acetylenic unsaturation), preferably a vinyl group, —CH═CH₂or allyl group.

The term “unsaturated non activated side groups” is defined as a groupcomprising one or more double carbon-carbon bonds with no electronwithdrawing groups, like C═O moieties, adjacent to the unsaturation.Accordingly, this term does not comprise acrylate or methacrylate groupsor styrene groups. Vinyl groups directly attached to a silicon atom(e.g. —O—Si—CH═CH₂ moieties, sometimes referred to as e.g. vinylfunctional siloxanes) are not comprised by the term “unsaturated nonactivated side groups”, either.

The curable composition preferably satisfies at least one, preferablytwo or more, and sometimes all of the following characteristics aftercuring:

-   -   Shore hardness D of the cured composition, measured according to        DIN 53505, above about 35, preferably above about 45, and more        preferably above about 60. Values up to about 95, up to about 90        or up to about 80 can be reached.    -   E-modulus of the cured composition above about 1000 MPa,        preferably above about 1200 MPa, and more preferably above about        2000 MPa.    -   Impact strength of the cured composition measured according to        DIN 53453 above about 1, preferably above about 2 kJ/m².    -   Flexural strength, measured according to DIN 51048, above about        60, and preferably above about 70 M Pa.    -   Compressive strength, measured according to ISO 7489, above        about 100, and preferably above about 110 MPa.

Representative viscosities for component (A) can be in a range of about0.01 Pa*s to about 50 Pa*s, or in a range of about 0.1 Pa*s to about 20Pa*s, or in a range of about 1 Pa*s to about 10 Pa*s, at 23° C.

Representative values for the molecular weight (Mw) of component (A) canbe in a range of about 500 gmole⁻¹ to about 100000 gmole⁻¹, or in arange of about 1000 gmole⁻¹ to about 20000 gmole⁻¹ or in a range ofabout 1500 gmole⁻¹ to about 10000 gmole⁻¹. The molecular weight can bedetermined with GPC.

Representative equivalent weights of component (A) can be in a range ofabout 68 to about 1000, or can be in the range of about 80 to about 500or in the range of about 90 to about 400, wherein the term equivalentweight is defined as follows:“equivalent weight” (EW)=(molecular weight)/(number of unsaturations inthe molecule)

For example: Tetraallylsilane: Molecular weight: 192 g/mole Number ofunsaturations: 4 (EW) = (192 g/mole)/4 =  48 g/mole

For molecules having a low molecular weight, the number of unsaturationscan be counted (cf. Example 4 given below). For molecules having ahigher molecular weight the equivalent weight (EW) can be determined bythe titration method described below: Device: 682 Titroprocessor(Metrohm, Switzerland) Chemicals: 0.1 N Sodium arsenite solution(NaAsO₂) Br₂/CH₂Cl₂ (about 3.2 ml Br₂ are disolved in CH₂Cl₂ p.a.)Methanol p.a. Electrode: 6.0431.100 Platinum Titrode (Metrohm,Switzerland)The sample to be determined is weighed into a 100 ml Erlenmeyer flaskwith ground neck (exactness 0.1 mg) and dissolved in 10.0 ml ofBr₂/CH₂Cl₂ reagent. After a reaction time of about 2 hours at roomtemperature, 50 ml of methanol p.a. are added and the sample is titratedwith 0.1 N sodium arsenite solution. Together with that two blank valuesare determined. The average value of these blank values is considered inthe calculation.Calculation:EW=((weight of sample[mg])*2)/((blank value [ml])−(volume of titrationof sample [ml])*(factor of NaAsO₂ solution [mole/l]))The value reported below is the average of three determined values.

The equivalent weight reflects the “density” of unsaturations in therespective molecule. The lower the value of EW, the more unsaturationsare present in the molecule. The unsaturated groups present in component(A) take part in the crosslinking reaction with crosslinker component(B). A highly crosslinked polymer usually shows a high hardness aftercuring.

Component (A) comprises at least 2 and may comprise up to about 50unsaturated organic side groups attached to Si atoms of the linearsiloxane backbone. Each side group can have 1, 2, 3 or more unsaturatedmoieties. The position of the unsaturation in the side group ispreferably terminal for the double carbon-carbon bond. Usually theunsaturations are identical in view of their chemical nature, e.g. onlyvinyl or only allyl. The total number of carbon-carbon double bonds incomponent (A) is at least 3, 4, 5, 6, 7, 8 or 10.

Useful compositions can be prepared using component (A) in an amount ofabout 1 to about 95 wt.-%. Another useful range is from about 5 to about75 wt.-%. A further useful range is from about 10 to about 60 wt.-%.

Crosslinker component (B) of the curable composition is a SiH-containingcomponent having a SiH functionality greater 1, preferably 2, 3, 4, 5, 6or more. Component (B) can react with component (A) in the presence ofcatalyst (C) via hydrosilation reaction. Component (B) can be present inthe claimed composition in an amount of about 1 to about 80 wt.-%.Another useful range is from about 5 to about 50 wt.-%. A further usefulrange is from about 10 to about 40 wt.-%. Component (B) may have aviscosity of greater than about 50 mPa*s, and sometimes greater thanabout 100 mPa*s.

The molecular weight (Mw) of component (B) can be greater than about 400g/mole or greater than about 600 g/mole. The molecular weight (Mw) ofcomponent (B) does usually not exceed about 10000 g/mole. Thus, themolecular weight (Mw) of component (B) can be within the range of about400 to about 10000 g/mole. The molecular weight can be determined withGPC.

Suitable compounds for component (B) include siloxane-substitutedhydrocarbons or polyethers having at least two SiH groups per molecule,for example like those described in U.S. Pat. No. 5,849,812(corresponding to DE 19 719 438 A1), the description of which regardingdefinition, synthesis and preferred embodiments should be considered aspart of the invention.

Suitable compounds for components (B) are also described in U.S. Pat.No. 5,086,148 the disclosure of which is incorporated by reference, too,and can be represented by formula (I):

wherein:

-   -   A is a straight-chain or branched 2- to 6-valent hydrocarbon        radical with 6 to 30 carbon atoms, containing at least one        aromatically unsaturated or cycloaliphatic ring,    -   B is a straight-chain or branched, saturated hydrocarbon radical        with 2 to 6 carbon atoms,    -   m=2 to 6;    -   n=0 to 25;    -   C′ represents the radical        wherein:

R⁰ to R³ are same or different, and are each H, methyl or ethyl;

e=0 to 8; f=1 to 2; g=0 to 8; h=0 to 4;

R⁴ to R¹⁰, are same or different, and are each H, methyl or ethyl, withthe proviso that at least 1 and at the most 5 of R⁴ to R¹⁰ are H,wherein g and h cannot simultaneously be 0.

In formula (I), radical A can be selected from the group consisting ofbivalent 1,4-phenylene, 2,7-naphthylene-,4,4′-isopropylidenediphenylene-, 4,4′-biphenylylene-, phthaloyl-,terephthaloyl- or tricycle-[5.2.1.02,6]-decan-3,8-dimethyl radicals.

Radical B can be an ethylene or propylene radical, m is preferably from2 to 4, n is preferably from 0 to 10, and more particularly from 0 to 3.In the radical C′, the radicals R⁰ to R³ are preferably H or methyl, Hin particular being preferred, and the radicals are the same, f ispreferably 2, R⁴ and R⁵ are preferably methyl, R⁶ is preferably H, R⁷and R⁹ are preferably methyl, R⁸ and R¹⁰ are preferably H, e ispreferably 0 to 5, and more particularly, 1 to 3, g is preferably 1 to 4and h is preferably 1 to 2. Radical C′ of the following formulas areparticularly preferred:

Especially preferred are compounds according to the formulas below:

wherein n=0, 1, 2 or 3.

The siloxane-substituted aromatic or cycloaliphatic compounds can beproduced according to methods known to the skilled person or asdisclosed in U.S. Pat. No. 4,877,854 the disclosure of which is hereinincorporated by reference (corresponding to DE 37 41 575 A1). They canbe produced by reacting a di- or poly-allyl or -vinyl aromatic compoundwith a polyorganosiloxane, which contains at least two SiH groups, usinga platinum catalyst in a mole ratio of at least two SiH groups to oneallyl- or vinyl-group. Suitable starting substances, are for example,the diallylether of bisphenol A, of ethoxylated bisphenol A and ofbishydroxymethyl-tricyclo-[5.2.1.0.sup.2,6]-decan as well as phthalicand terephthalic acid diallyl ester. The catalyst used should be removedto produce storage-stable pastes. This can suitably be achieved by theadsorption of the catalyst with silica gel, diatomaceous earth or thelike.

Suitable hydrosilation catalyst components (C) which can be used in theinvention include those compounds which promote or facilitate theaddition reaction between the ethylenically unsaturated groups and thesilicon-bonded hydrogen groups of components (A) and (B), respectively.

The catalyst can contain Pt and can be a Karsted catalyst. The catalystcan be prepared from hexachloroplatinum acid by reduction withtetramethyldivinyldisiloxane. Such compounds are known to the skilledperson. Any other platinum compounds which can catalyze or accelerateaddition cross-linking of silanes with ethylenically unsaturated doublebonds are also suitable. Platinum-siloxane complexes as described, e.g.,in U.S. Pat. No. 3,715,334, U.S. Pat. No. 3,775,352 and U.S. Pat. No.3,814,730 are suitable. The disclosure of these patents with regard toplatinum complexes and their preparation is explicitly mentioned andexpressly regarded as part of the disclosure of the invention.

The amount of the platinum complex catalyst should be sufficient toprovide the desired degree of crosslinking of the organopolysiloxanecompound within a reasonable time. Due to the wide range of acceptablemolecular weights for the addition-curable compound, it is presentlybelieved that this amount is best described in terms of the ratio of Ptatoms to functional groups in the composition. Thus, catalyst component(C) can be used e.g. in an amount of about 0.00005 to about 0.05 wt.-%.Another useful range is form about 0.0002 to about 0.04 wt.-%, eachcalculated as elemental platinum and related to the overall weight ofthe composition.

Examples of suitable catalysts include platinum or platinum compoundcatalysts exemplified by chloroplatinic acid, a complex ofchloroplatinic acid and an alcohol, a complex of platinum and an olefin,a complex of platinum and a ketone, a complex of platinum and avinylsiloxane, colloidal platinum, a complex of colloidal platinum and avinylsiloxane etc., palladium, a mixture of palladium black andtriphenylphosphine, etc., or rhodium or rhodium compound catalysts.Preferred is a complex of Pt with 1,1,3,3-tetramethyl divinyldisiloxane.

The composition of the invention also includes filler component (D),preferably a mixture of fillers. A wide variety of inorganic, especiallyhydrophobic fillers may be employed such as silicas, aluminas,magnesias, titanias, inorganic salts, metallic oxides and glasses. Ithas been found to be possible to employ mixtures of silicone dioxides,including those derived from crystalline silicone dioxide, such aspulverized quartz (4 to 6 μm); amorphous silicone dioxides, such as adiatomaceous earth (4 to 7 μm); and silanated fumed silica, such asCab-o-Sil TS-530 (160-240 m²/g), manufactured by Cabot Corporation.Varying the sizes and surface areas of the foregoing materials enablesone to control the viscosity and thixotropicity of the resultingcompositions. Some or all of the foregoing hydrophobic fillers may besurface treated with one or more silanating agents, as known to those ofordinary skill in the art. Such silanating may be accomplished, e.g.,using known halogenated silanes or silazides.

Filler component (D) can be present in an amount of from about 4 toabout 90 wt.-%, or about 20 to about 80 wt.-%, or about 30 to about 75wt.-% of the total composition.

Among the fillers which can be used are non-reinforcing fillers such asquartz, cristobalite, calcium silicate, diatomaceous earth, zirconiumsilicate, montmorillonite such as bentonite, zeolite, includingmolecular sieves such as sodium aluminium silicate, metal oxide powdersuch as aluminium or zinc oxide or their mixed oxides, barium sulphate,calcium carbonate, plaster, glass and plastic powder. Thenon-reinforcing fillers can be surface treated. The surface treatmentcan generally be carried out with the same methods as described for thereinforcing fillers.

Suitable fillers also include reinforcing fillers such as e.g. pyrogenicor precipitated silicic acid and silica aluminium mixed oxides. Theabove mentioned fillers can be hydrophobized, for example by treatmentwith organosilanes or siloxanes or by the etherification of hydroxylgroups to alkoxy groups. One type of filler or also a mixture of atleast two fillers can be used. The particle distribution is preferablychosen such that there are no fillers with particle sizes of more than50 μm.

A combination of reinforcing and non-reinforcing fillers can bedesirable. In this respect, the quantity of reinforcing fillers mayrange from about 0.1 to about 15 wt.-%, in particular from about 1 toabout 10 wt.-%. The difference in the named overall ranges, i.e. about 9to about 80 wt.-%, can be accounted for by non-reinforcing fillers.

Pyrogenically-prepared, highly-disperse, silicic acids which can behydrophobized by surface treatment are useful as reinforcing fillers.The surface treatment can be carried out, e.g. withdimethyldichlorosilane, hexamethyldisilazane,tetramethylcyclotetrasiloxane or polymethylsiloxane.

To control the reactivity of the addition reaction and to preventpremature curing, it may be advantageous to add an inhibitor (E) whichprevents the addition reaction for a specific period of time or slowsthe addition reaction down. Such inhibitors are known and described,e.g. in U.S. Pat. No. 3,933,880, the disclosure of which regarding suchinhibitors and their preparation is expressly regarded as being part ofthe disclosure of the invention and is herein incorporated by reference.

Examples of such inhibitors are acetylenic unsaturated alcohols such as3-methyl-1-butyne-3-ol, 1-ethynylcyclohexane-1-ol,3,5-dimethyl-1-hexyne-3-ol and 3-methyl-1-pentyne-3-ol. Examples ofinhibitors based on an vinyl siloxane are1,1,3,3-tetramethyl-1,3-divinyl siloxane and poly-, oligo- anddisiloxanes containing vinyl groups.

The optional inhibitor can be present in an amount of up to about 0.3wt.-% based on the composition, preferably in an amount of up to about0.15 wt.-%.

Other optional additives (F) include those useful or advantageous fordental materials. For example, optional additives may include modifiers,dyes, pigments, thixotropic agents, flow improvers, polymericthickeners, surfactants, odorous substances, diluting agent(s) andflavourings. Additives may be added alone or in admixture, and can beused to adjust the rheological characteristics.

The other optional additives can be present in an amount being in therange of about 0.05 to about 20 wt.-%, preferably in the range of about0.1 to about 15 wt.-% with respect to the cured composition.

Thus, the inventive composition can comprise

-   -   component (A) in an amount in the range of about 1 wt.-% to        about 95 wt.-%, or in an amount in the range of about 5 wt.-% to        about 75 wt.-%, or in an amount in the range of about 10 wt.-%        to about 60 wt.-%;    -   crosslinker component (B) in an amount in the range of about 1        wt.-% to about 80 wt.-% or in an amount in the range of about 5        wt.-% to about 50 wt.-%, or in an amount in the range of about        10 wt.-% to about 40 wt.-%;    -   catalyst component (C) in an amount of in the range of about        0.00005 wt.-% to about 0.05, wt.-%, or in an amount in the range        of about 0.0002 wt.-% to about 0.04 wt.-%;    -   filler component (D) in an amount in the range of about 3.99995        wt.-% to about 90 wt.-% or in an amount in the range of about        19.9998 wt.-% to about 80 wt.-%, or in an amount in the range of        about 29.9998 wt.-% to about 75 wt.-%;    -   optional inhibitor (E) in an amount in the range of about 0.001        wt.-% to about 0.3 wt.-%—or in an amount in the range of about        0.01 wt.-% to about 0.15 wt.-%;    -   optional additive (F) in an amount in the range of about 0.05        wt.-% to about 20 wt.-%—or in an amount in the range of about        0.1 wt.-% to about 15 wt.-%;    -   with respect to the cured composition.

Surprisingly it has been found that reacting component (A) withcrosslinker component (B) results in hard materials, which are notbrittle and have excellent physical properties, especially a highhardness. In a preferred embodiment, the composition cures to a hardproduct (e.g. having a detectable Shore hardness) under ambientconditions, e.g. at about 23° C. to about 25° C. within about 30 min orabout 20 min or about 10 min.

It has also been found that the hard materials obtained show onlynegligible adhesion to silicone impression materials used in the dentalfield, even if the chemical basis of both the hard materials obtainedwhen curing the inventive compounds and the silicone impression materialare similar. This effect is especially advantageous using the inventivecomposition for the production of provisional crown and bridgematerials. Having taken the impression of the dental situation with asilicone impression material the cured impression is hereinafter filledwith a provisional crown and bridge material. In this respect theprovisional crown or bridge material after curing should not show strongadhesion to the impression material.

When using the inventive composition for the production of a modellingmaterial, the composition is poured into an impression to obtain a modelof the dental situation of a patient. The situation can be compared tothe above described procedure for obtaining a provisional crown andbridge material. The model material, after curing, should not showstrong adhesion to the impression material, either.

A further surprising effect is that component (A) can have a relativelyhigh content of unsaturated moieties in relation to its molecularweight, sometimes combined with relatively low viscosity.

Component (A) may be obtained by a standard hydrosilation reaction knownto the skilled person using linear, multifunctional SiH containingsiloxanes and organic molecules that comprise two or more carbon-carbonunsaturations that are of equivalent reactivity towards hydrosilation.

The synthesis of component (A) can be done e.g. by hydrosilationreaction of an at least bifunctional terminal unsaturated organiccompound represented by formula (1)[A(B)_(b)]_(a)C¹¹   (1)wherein

-   A=linear or branched terminally unsaturated aliphatic residue    (preferably comprising 2 to 20, or 3 to 10 C atoms), wherein the    unsaturation is a C—C double bond not activated by a conjugated    carbonyl group (e.g. vinyl, ethynyl, propynyl, allyl, butenyl,    hexenyl, decenyl, p-ethenyl, styryl);-   B=O, (O═)C—O, O—C(═O), O—C(═O)—O, NH, S (not conjugated to the    unsaturation of A);-   C¹¹=H or aliphatic, cycloaliphatic or aromatic organic or silicon    organic residue comprising 1 to 50, or 1 to 35 C atoms and    additionally up to 6 hetero atoms like O, N or S which can also be    part of a ring system, being a-fold radically;-   a=2, 3, 4, 5, 6, 7, 8, 9 or 10;-   b=0 or 1    with an at least bifunctional hydrido silicone compound represented    by formula (2):    wherein-   R1=alkyl, aryl or alkaryl each comprising 1 to 20 C atoms, wherein    at least one of the H atoms can be substituted by halogen atoms    (e.g. chlorine or fluorine) or alkyl groups (e.g. methyl, ethyl,    propyl, butyl, phenyl or cyclohexyl);-   R2=H, R1 or alkenyl with 1 to 10 C atoms, preferably H, methyl,    vinyl, allyl or butenyl;-   n=0 to 500, or 0 to 100, or 1 to 50;-   m=0 to 500, or 0 to 100, or 1 to 50.    and optionally with a further unsaturated alky, aryl or alkaryl    compound bearing only one unsaturated moiety and comprising 1 to 20    or 2 to 10 C atoms (e.g., ethylene, styrene, 1-hexene), wherein one,    a part or all of the H atoms can be substituted by halogen atoms.

This reaction will lead to a preferred embodiment of component (A) whichcan be represented by formula (3): (3)

wherein:

-   R1=alkyl, aryl or alkaryl each comprising 1 to 20 carbon atoms,    preferably 1 to 10 carbon atoms, wherein one or more (and sometimes    all) of the carbon atoms can be substituted with halogen atoms    (e.g., fluorine or chlorine) or alkyl groups (e.g. methyl, ethyl,    propyl, butyl, phenyl or cyclohexyl);-   R2=is either equal to R1 or, in the case where p is 0, R4;-   R3=alkyl, aryl or alkaryl group comprising 1 to 20 carbon atoms,    wherein at least one of the H atoms can be substituted by halogen    atoms, preferably ethyl, hexyl, octyl decyl, 2-phenylethyl, dodecyl,    tetradecyl, hexadecyl or octadecyl;-   R4=linear or branched, terminally unsaturated aliphatic,    cycloaliphatic or aromatic organic or silicon organic residue moiety    having (a-1) ethylenic unsaturations, wherein a is as defined above,    and wherein such unsaturations are carbon-carbon double bonds not    activated by a conjugated carbonyl group (e.g., vinyl, ethynyl,    propynyl, allyl, 3-butenyl, 5-hexenyl, 9-decenyl, p-ethenyl-styryl),    wherein the moiety comprises preferably 1 to 50 carbon atoms, or 5    to 30 carbon atoms, and additionally up to 6 oxygen atoms which can    also be part of a ring system;-   o=0 to 12, or 0 to 8, or 0 to 5, or 0 to 2;-   m=0 to 50, or 0 to 35, or 0 to 20, or 0 to 10;-   p=0 to 500, or 1 to 100, or 2 to 75, or 5 to 50.    Preferably (o+m+p) is about 0 to 500, or 1 to 100, or 2 to 75, or 5    to 50.

During hydrosilation, unsaturated compound (1) reacts with the SiHmoiety of compound (2) and turns into R4. The reaction usually resultsin a mixture of the α- and the β-adduct. The formulas used in thedescription always show the β-adduct. However, the α-adduct may also bepresent.

In this respect it should be mentioned that the compound according toformula (3) is idealized in that it only shows the reaction product ofcompounds according to formula (1) with compounds according to formula(2), whereas both compounds are oligofunctional. Without wishing to belimited to any particular mechanism, it is assumed that a minorcrosslinking reaction takes place not shown in the formulas.Surprisingly, it has been found that the assumed crosslinking reactiondoes not result in a significant thickening or gelling of the resultingcompounds. The resulting compounds remain capable of flowing.

Although the extent of chain extension during this reaction—due toreaction of any remaining unsaturation in R4 with a second siliconechain—is so low that the products obtained have a relatively lowviscosity, chain extension may still occur to a certain amount. This maybe illustrated by the example given in the formula below.

What can also be taken from this example is, that residual SiH groupsmay remain in the molecule. It can also be calculated by stoichiometry,that only a fraction of the initial SiH content of the compoundaccording to formula (2) reacts with compounds according to formula (1).The rest can be saturated, if desired, by addition of, and hydrosilationwith optionally unsaturated compounds containing alkyl, aryl or alkarylresidues mentioned above (e.g. ethylene, styrene, hexene) to giveresidue R3 at the given silicon atom. A fraction of 0 up to 25% of theinitial SiH residues in the chain may be saturated in this way.

Compounds according to formula (3) can also be obtained via a differentway. For example, suitable dihalogen- or dialkoxysilanes or thecorresponding mixture of such silanes can be hydrolysed combined withsubsequent condensation in the presence of suitable chain-terminatinggroups.

In one embodiment, one may react compounds according to formula (1), forexample with dichlormethylsilane using a standard hydrosilationreaction. The product obtained might then be hydrolysed and condensed inthe presence of hexamethyldisiloxane. This will also result in compoundsaccording to formula (3). The hydrolysis and condensation can also beconducted in the presence of a silane, like methyl-phenyldichlorosilane.

The preparation of corresponding molecules can be achieved, e.g.,according to standard procedures which are portrayed in W. Noll, “Chemieund Technologie der Silikone”, Verlag Chemie Weinheim 2nd edition 1968,pages 162-206 or J. Burghardt, Chemie und Technologie der Polysiloxanein “Silikone, Chemie und Technologie”, Vulkan Verlag, Essen, 1989, pages23-37.

Surprisingly, for linear siloxanes, and in contrast to many cyclicsiloxanes, the hydrosilation reaction does not lead to an unacceptableincrease of viscosity or gelation of the polymer to such an extent thatit is not useful in dental formulations. Thus, the invention is alsodirected to the product obtainable by reacting compound (1) withcompound (2) as defined above.

Representative compounds according to formula (1) include di- , tri- orhigher unsaturated functionality. A functionality of unsaturation ofabout 2 to about 10 is preferred, although about 2 to about 6 can beeven more preferred.

The compounds according to formula (1) may be further characterized bythe term equivalent weight as defined above. The compounds according toformula (1) generally have an (EW) varying between about 27 g/mole andabout 500 g/mole, or between about 34 g/mole and about 350 g/mole. Themolecular weight of compound (1) can be in the range of about 54 g/moleto about 1000 g/mole, or about 68 g/mole to about 800 g/mole.

Examples of useful compounds according to formula (1) are:

-   Diallylether (A=Vinyl, a=2, b=0, C=2-Oxo-propane-1,3-diyl);-   Diallylcarbonate (A=Allyl, a=2, b=1, B=O, C=Carbonyl);-   Ethyleneglycoldiallylcarbonate (A=Allyl, a=2, b=1, B=O,    C=1,2-Bis-(carbonyloxy)ethane);-   Diethyleneglycoldiallylcarbonate (A=Allyl, a=2, b=1, B=O,    C=Bis-(carbonyloxyethyl)ether);-   Pentaerythritol-tetraallylether (A=Allyl, a=4, b=1, B=O,    C=Tetrakis-(methylene)-methane);-   Di-Pentaerythritol-hexaallylether (A=Allyl, a=6, b=1, B=O,    C=Bis-[tetra-(methylene)-methane)ether;-   Trimethylolethane-triallylether (A=Allyl, a=3, b=1, B=O,    C=Methyl-tris-(methylene)-methane);-   Trimethylolpropane-triallylether (A=Allyl, a=3, b=1, B=O,    C=Ethyl-tris-(methylene)-methane);-   Ethyleneglycol-diallylether (A=Allyl, a=2, b=1, B=O,    C=Ethane-1,2-diyl);-   Diethyleneglycoldiallylether (A=Allyl, a=2, b=1, B=O,    C=3-Oxa-pentane-1,5-diyl);-   1,2-Propanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Propane-1,2-diyl);-   1,3-Propanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Propane-1,3-diyl);-   1,3-Butanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Butane-1,3-diyl);-   1,4-Butanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Butane-1,4-diyl);-   1,4-Butenedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Butene-1,4-diyl);-   1,4-Butynedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Butyne-1,4-diyl);-   1,5-Pentanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Pentane-1,5-diyl);-   1,6-Hexanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Hexane-1,6-diyl);-   1,8-Octanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Octane-1,8-diyl);-   1,9-Nonanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Nonane-1,9-diyl);-   1,10-Decandioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Decan-1,10-diyl);-   1,12-Dodecanedioldiallylether (A=Allyl, a=2, b=1, B=O,    C=Dodecane-1,12-diyl)-   Glycerol-triallylether (A=Allyl, a=4, b=1, B=O,    C=Propane-1,2,3-triyl);-   1,2,4-Butanetrioltriallylether (A=Allyl, a=3, b=1, B=O,    C=Butane-1,2,4-triyl);-   1,2,6-Hexanetrioltriallylether (A=Allyl, a=3, b=1, B=O,    C=Hexane-1,2,4-triyl);-   Diglyceriol-tetraallylether (A=Allyl, a=4, b=1, B=O,    C=4-Oxa-heptane-1,2,6,7-tetryl);-   Erythritol-tetraallylether (A=Allyl, a=4, b=1, B=O,    C=Butane-1,2,3,4-tetryl);-   Mannite-hexaallylether (A=Allyl, a=6, b=1, B=O,    C=Hexane-1,2,3,4,5,6-hexyl);-   Sorbitol-hexaallylether (A=Allyl, a=6, b=1, B=O,    C=Hexane-1,2,3,4,5,6-hexyl);-   Inositol-hexaallylether (A=Allyl, a=6, b=1, B=O,    C=Cyclohexane-1,2,3,4,5,6-hexyl);-   Oxalic acid diallylester (A=Allyl, a=2, b=O, C=Ethanedione);-   Malonic acid diallylester (A=Allyl, a=2, b=O, C=1,3-Propanedione);-   Succinic acid diallylester (A=Allyl, a=2, b=O, C=1,4-Butanedione);-   Adipic acid diallylether (A=Allyl, a=2, b=O, C=1,6-Hexanedione);-   Sebacic acid diallylether (A=Allyl, a=2, b=O, C=1,8-Octanedione);-   “Santolink XI 100” (from Monsanto) (polymeric A=Allyl, a=1-20, b=O,    C=oligomeric backbone of 2-(methylene)ethyloxy repetition units);-   Dimethyldiallylsilane (A=Vinyl, a=2, b=0,    C=2-Dimethylsilyl-1,3-propanediyl);-   Divinyldimethylsilane (A=Vinyl, a=2, b=0, C=Dimethylsilanediyl);-   Diphenyldiallylsilane (A=Vinyl, a=2, b=0,    C=2-Diphenylsilyl-1,3-propanediyl);-   Diphenyldivinylsilane (A=Vinyl, a=2, b=0, C=Diphenylsilanediyl);-   Triallylmethylsilane (A=Vinyl, a=3, b=0,    C=Methyl-tris-(methylene)-silane);-   Trivinylmethylsilane (A=Vinyl, a=3, b=0, C=Methylsilanetriyl);-   Tetraallylsilane (A=Vinyl, a=4, b=0, C=Tetrakis-(methylene)-silane);-   Tetravinylsilane (A=Vinyl, a=4, b=0, C=Silanetetryl);-   Bis-(4-allyloxyphenyl)-sulfone (A=Allyl, a=2, b=1, B=O,    C=Bis-(p-phenylene)-sulfon); C₁₈H₁₈O₂S; EW=149 g/mole-   Bis-(4-allyloxyphenyl)-keton (A=Allyl, a=2, b=1, B=O,    C=Bis-(p-phenylene)-ketone); C₁₉H₁₈O₃; EW=147 g/mole-   Bis-(4-allyloxyphenyl)-methane (A=Allyl, a=2, b=1, B=O,    C=Bis-(p-phenylene)-methane); C₁₉H₂₀O₂; EW=140 g/mole-   1,1-Bis-(4-allyloxyphenyl)-ethane (A=Allyl, a=2, b=1, B=O,    C=1,1-Bis-(p-phenylene)-ethane);-   2,2-Bis-(4-allyloxyphenyl)-propane (A=Allyl, a=2, b=1, B=O,    C=2,2-Bis-(p-phenylene)-propane); C₂₁H₂₄O₂; EW=154 g/mole-   2,2-Bis-(4-allyloxyphenyl)-perfluoropropane (A=Allyl, a=2, b=1, B=O,    C=2,2-Bis-(p-phenylene)-perfluoropropane); C₂₁H₁₈F₆O₂; EW=208 g/mole-   2,2-Bis-(4-allyloxy-3,5-dibromo-phenyl)-propane (A=Allyl, a=2, b=1,    B=O, C=2,2-Bis-(4-phenylene-3,5-dibromo)-propane); C₂₁H₂₀Br₄O₂;    EW=312 g/mole-   3,3-Bis-(4-allyloxyphenyl)-pentane (A=Allyl, a=2, b=1, B=O,    C=3,3-Bis-(p-phenylene)-pentane);-   4,4-Bis-(4-allyloxyphenyl)-heptane (A=Allyl, a=2, b=1, B=O,    C=2,2-Bis-(p-phenylene)-heptane); C₂₅H₃₂O₂; EW=182 g/mole-   1,1-Bis-(4-allyloxyphenyl)-cyclopentane (A=Allyl, a=2, b=1, B=O,    C=1,1-Bis-(p-phenylene)-cyclopentane); C₂₃H₂₆O₂; EW=167 g/mole-   1,1-Bis-(4-allyloxyphenyl)-cyclohexane (A=Allyl, a=2, b=1, B=O,    C=1,1-Bis-(p-phenylene)-cyclohexane); C₂₄H₂₈O₂; EW=174 g/mole-   1,1-Bis-(4-allyloxyphenyl)-3,3,5-trimethylcyclohexane (A=Allyl, a=2,    b=1, B=O, C=1,1-Bis-(p-phenylene)-3,3,5-trimethylcyclohexane);    C₂₇H₃₄O₂; EW=195 g/mole-   1,1,1-Tris-(4-allyloxyphenyl)-ethane (A=Allyl, a=3, b=1, B=O,    C=1,1,1-Tris-(p-phenylene)-ethane);-   Bis-(allyloxy)-tricyclo[5.2.1.0^(2.6)]decane (A=Allyl, a=2, b=1,    B=O, C=tricyclo[5.2.1.0^(2.6)]decane).

Many suitable bifunctional hydrido silicone compounds according toformula (2) are known in the art.

Representative compounds according to formula (2) can comprise terminaland/or pendant SiH groups. Compound (2) can be defined as a moleculeonly in the case of disiloxane (R2=H, n=m=0). Otherwise it is a siliconepolymer with a chain length distribution and polydispersity typical forsilicone polymers (Encyclopedia of Polymer Science and Engeneering2^(nd) Edition, Vol 15 pages 204-308).

Typically, the siloxane polymers have pendant or terminal SiHfunctionality. In some cases, especially for siloxane polymers having alow molecular weight both can be the case. A silicon atom usually doesnot have more than one SiH functional group but there can be siliconatoms with no SiH function like in terminal functional silicones, withall non-terminal silicon atoms, and in pendant functional siliconecopolymers with the co-monomer being not SiH functional.

The average chain length (m+n+2)—according to formula (2)—of suchsilicone polymer samples generally is low and does usually not exceedabout 500 Si-atoms, can sometimes be lower than about 100 Si-atomssometimes be lower than about 75 Si-atoms or can be in the range ofabout 5 to about 50 Si-atoms. The average number of SiH groups in suchpolymers will usually not exceed about 50 SiH-groups, sometimes notexceed about 35 SiH-groups, sometimes not exceed about 20 SiH-groups orsometimes not exceed about 10 SiH groups. In terminal functionalsiloxanes or silicone polymers the SiH functionality can be as low as 2.

The average M_(n) of compound (2) usually does not exceed about 20000g/mole, preferably does not exceed 10000 g/mole. The average M_(n) ofcompound (2) can be up to or below about 8000 g/mole.

Examples of useful compounds according to formula (2) are:

-   Methylhydrogensiloxane-Polymers with Trimethylsiloxy-Endgroups    (R1=Methyl, R2=Methyl, n=100% von (n+m), Ø_((n+m))<50); M_(n)<3200    g/mole-   Methylhydrogensiloxane-Polymers with    Dimethylhydrogensiloxy-Endgroups (R1=Methyl, R2=H, n=100% von (n+m),    Ø_((n+m))<50); M_(n)<3200 g/mole-   Methylhydrogensiloxane-co-Dimethylsiloxane-Copolymers with    Trimethylsiloxy-Endgroups (R1=Methyl, R2=Methyl, 20%<n<70% von    (n+m), Ø_((n+m))<50); M_(n)<3700 g/mole-   Methylhydrogensiloxane-co-Dimethylsiloxane-Copolymers with    Dimethylhydrogensiloxy-Endgroups (R1=Methyl, R2=H, 20%<n<70% von    (n+m), Ø_((n+m))<50); M_(n)<3700 g/mole-   Phenylhydrogensiloxane-Polymers with Trimethylsiloxy-Endgroups    (R1=Phenyl bzw. Methyl, R2=Methyl, n=100% von (n+m), Ø_((n+m))<50);    M_(n)<6300 g/mole-   Phenylhydrogensiloxane-Polymers with    Dimethylhydrogensiloxy-Endgroups (R1=Phenyl bzw. Methyl, R2=H,    n=100% von (n+m), Ø_((n+m))<50); M_(n)<6300 g/mole-   Phenylhydrogensiloxane-co-Dimethylsiloxane-Copolymers with    Trimethylsiloxy-Endgroups (R1=Phenyl bzw. Methyl, R2=Methyl,    20%<n<70% von (n+m), Ø_((n+m))<50); M_(n)<5600 g/mole-   Phenylhydrogensiloxane-co-Dimethylsiloxane-Copolymers with    Dimethylhydrogensiloxy-Endgroups (R1=Phenyl bzw. Methyl, R2=H,    20%<n<70% von (n+m), Ø_((n+m))<50); M_(n)<5600 g/mole-   Methylhydrogensiloxane-co-Phenylmethylsiloxane-Copolymers with    Trimethylsiloxy-Endgroups (R1=Methyl bzw. Phenyl, R2=Methyl,    20%<n<70% von (n+m), Ø_((n+m))<50); M_(n)<5700 g/mole-   Methylhydrogensiloxane-co-Phenylmethylsiloxane-Copolymers with    Dimethylhydrogensiloxy-Endgroups (R1=Methyl bzw. Phenyl, R2=H,    20%<n<70% von (n+m), Ø_((n+m))<50); M_(n)<5700 g/mole-   Dimethylsiloxane-Polymers with Dimethylhydrogensiloxy-Endgroups    (R1=Methyl, R2=H, m=100% von (n+m), Ø_((n+m))<10); M_(n)<900 g/mole-   Diphenylsiloxane-Polymers with Dimethylhydrogensiloxy-Endgroups    (R1=Phenyl bzw. Methyl, R2=H, m=100% von (n+m), Ø_((n+m))<10);    M_(n)<2100 g/mole-   Phenylmethylsiloxane-Polymers with Dimethylhydrogensiloxy-Endgroups    (R1=Methyl bzw. Phenyl, R2=H, m=100% von (n+m), Ø_((n+m))<10);    M_(n)<1440 g/mole.

The curable compositions of the invention are usually pre-mixed into twoor more parts prior to use. For example, one part may contain component(A) and catalyst (C), e.g. a platinum containing catalyst, while asecond part may contain crosslinker component (B) and optionally otherunsaturated containing organopolysiloxanes such as polydimethylsiloxaneswith terminal dimethyl-vinyl-siloxy-groups.

Therefore, the invention also relates to a kit of parts, comprising abase part (I) and a catalyst part (II), wherein the base part (I)comprises components (A) and (B), and the catalyst part (II) comprisescomponent (C), and wherein component (D) is present either in the basepart or the catalyst part or in the base part and the catalyst part. Theother optional component(s) (E) and (F) can be present either in thebase part or the catalyst part or in the base part and the catalystpart.

The invention also relates to a method of producing a curablecomposition comprising the steps i) providing components (A), (B), (C),(D) and optionally (E) and (F), ii) mixing the components.

The dosing of the components can be carried out by sight (strand-lengthcomparison), by weight, via pre-dosed pack units and subsequent manualmixing, from double-chambered cartridges with static mixing tubes or bymeans of volume dosing systems with downstream static or dynamic mixers.

Due to the low viscosity of component (A) and the absence of a smearlayer component (A) is especially useful for producing hard materials,for examples coatings, varnishes, plastics and dental materials.

The term “dental materials” comprises filling materials (provisional andpermanent), cements, provisional crown and bridge materials, modellingmaterials, bite registration materials, and materials used in theprosthodontic field.

If used in the dental field, the composition can be applied using e.g.the following steps: providing the components of the composition, mixingthe components, applying the composition to a surface, letting thecomposition cure.

The surface can be the surface of soft or hard oral tissue, the surfaceof an impression material, preferably of a cured impression material,the surface of a crown or the surface of a model of a tooth stump.

The invention is hereinafter described by examples without limiting thescope of the invention.

EXAMPLES

Measurements

The measurements were done at standard temperature and pressure (“STP”,i.e. 25° C. and 1023 hPas) according to the methods described below. Themeasurements were performed on the basis of specimens obtained aftermixing the respective basis and catalyst pastes, curing the compositionfor one hour at room temperature and hereinafter storing the curedcomposition for 23 hours at 36° C. in water.

The compressive strength was measured according to ISO 7489. Cylindricalspecimens (height 8 mm, diameter 4 mm) were tested using a ZwickUniversal Testing Machine Z 010 (speed 4 mm/min, force 10 N, speed 10mm/min).

The flexural strength was determined according to DIN 51048 using(cuboid specimen, height 4 mm, width 6 mm, length 25 mm, span 20 mm,speed 2 mm/min).

The E-modulus was determined using the measurement of flexural strengthbetween 20 and 50% of F_(max) according to the following formula:E=[IV ³/(4*b*h ³)]*[(XH−XL)/ΔL]wherein:

-   E=E-Modulus [N/mm³]-   IV=span [mm]-   b=width of the specimen-   h=height of the specimen-   XH=upper point of the determination of the E-Modulus-   XL=lower point of the determination of the E-Modulus-   ΔL=bending value between XH and XL [mm]

The tensile strength was determined according to DIN 53455 using a ZwickUniversal Testing Machine Typ 1455. Slightly modified specimens wereused (l=25 mm; b=2 mm; h=2 mm; speed=2 mm/min).

The impact strength was determined according to DIN 53453 using a Zwickimpact testing machine 5113 with a 0.5 J pendulum (width of indentedspecimen 6 mm, height 4 mm, length 50 mm).

The viscosity can be measured with a Haake Rotovisco RV20 device(spindle MV, measuring cup NV). the viscosity was measured at 23° C.After activation and rectification of the system, spindle MV wasinstalled. Following, the material to be measured was filled into themeasuring cup NV. Without undue delay, the spindle was lowered into themeasuring cup NV. The spindle should be covered by a layer of max. 1 mm.The material to be measured was tempered for 20 min at 23° C. Themeasurement was started and the viscosity values (mPas) were recordedstarting 20 s after the start of measurement. It has to be taken care ofthat at no time the measuring cup NV itself may rotate or move at all. Avalue for the viscosity was obtained in mPa*s. The above mentionedmethod of measurement corresponds to DIN 53018-1.

The shore hardness D of the cured composition of the invention wasmeasured according to DIN 53505 with a durometer (specimen: disc with adiameter of 38 mm and a height of 6 mm; measurement taken 24 h aftermixing the components).

The molecular weight (M_(w)) was determined with gel permeationchromatography (GPC). Calibration was done using commercially availablepolystyrol (PS) samples with narrow molecular weight distributions.Appropriate methods are known by the expert as described in “PolymerAnalysis”, Barbara Stuart, John Wiley (ISBN 0471899267 (Hb),_pages 108to 112. In addition the determination of the molecular weight can bedone using nuclear magnetic resonance spectroscopy (end-groupdetermination).

If not indicated otherwise, all chemical compounds used are commerciallyavailable from Aldrich, Fluka, Acros, ABCR or Gelest.

Example 1 Synthesis of a Component (A) using a H-Siloxane andPentaerythrit Tetraallylether

16.6 g Pentaerythritol-tetraallylether [M=280.45; 0.059 Mole] were addedto a heated mixture of 5 g of a Methylhydridosilicone oil [M=550; n=6.5;0.0091 Mole], 60 mg 5% platinum on carbon and 10 ml of toluene such thatno hydrogen evolution was observed. The reaction mixture was stirreduntil the SiH-absorption in the IR-Spectrum located at about 2100 cm⁻¹had disappeared. After workup and isolation of the product 20.5 g of aclear colorless oil was obtained with an (EW) of 130 g/mole.

Example 2 Synthesis of a Component (A) using a H-Siloxane andTetraallylsilane

24.9 g Tetraallylsilane [M=192.38; 0.13 Mole] were added to a heatedmixture of 10 g of a Methylhydridosilicone oil [M=2470; n=32; 4.05mMole], 120 mg 5% platinum on carbon and 20 ml of tolulene such that nohydrogen evolution was observed. The reaction mixture was stirred untilthe SiH-absorption in the IR-Spectrum located at about 2100 cm⁻¹ haddisappeared. After workup and isolation of the product 33.5 g of a clearcolorless and viscous oil was obtained with an (EW) of 93 g/mole.

Example 3 3. a) Synthesis of component (A) using a H-Siloxane andTetraallylsilane

12.45 g Tetraallylsilane [M=192.38; 0.13 Mole] were added to a heatedmixture of 10 g of a Methylhydridosilicone oil [M=2470; n=32; 4.05mMole], 120 mg 5% platinum on carbon and 20 ml of toluene such that nohydrogen evolution was observed. The reaction mixture was stirred untilthe SiH-absorption in the IR-Spectrum located at about 2100 cm⁻¹ wasconstant.

3. b) Synthesis of Component (A) using the Compound obtained in Example3 a) and Styrene

Thereafter to the reaction mixture of 3. a) 6.8 g of styrene [M=104.15;0.065 M] were added slowly. The reaction mixture was stirred until theSiH-absorption in the IR-Spectrum located at about 2100 cm⁻¹ haddisappeared. After workup and isolation of the product 27.5 g of a clearcolourless and viscous oil was obtained with an (EW) of 160 g/mole.

Example 4 Synthesis of Component (A) using 1,1,3,3-Tetramethyldisiloxaneand Tetraallylsilane

5 g Tetramethyldisiloxane, 50 ml Toluene, 64.1 mg Pt on Carbon (10% Pt),12.8 mg Brenzcatechine and 12.8 mg Al-Cupfferone were placed in a roundbottom flask and heated to reflux. 16.9 g Tetraallylsilane (92.6% pure)were added dropwise. Reflux was continued until SiH-band in IR spectrumat ˜2100 cm⁻¹ vanished. After filtration and workup 15.6 g of a clearyellow liquid remained with no residual SiH and a (EW) of 93 wasobtained.

Example 5 Synthesis of Component (A) using Poly(hydrogenemethyl)siloxane and Bisphenole A diallylether

10 g Poly(hydrogene methyl)siloxane (100% n, n˜7), 150 ml Toluene, 191.5mg Pt on Carbon (10% Pt), 38.3 mg Brenzcatechine and 38.3 mgAl-Cupferrone were placed in a round bottom flask and heated to reflux.51.4 g Bisphenole A diallylether were added drop-wise. Reflux wascontinued until SiH-band in IR spectum at ˜2100 cm⁻¹ no longerdecreased. After workup 60 g of a yellow liquid was obtained. Viscosity:0.77 Pa*s, (EW) of 266 g/mole.

Example 6 Synthesis of Component (A) using Poly(hydrogenemethyl)siloxane and 1,5-Hexadiene

20 g Poly(hydrogene methyl)siloxane (100% n, n˜7), 175 ml Toluene, 199.1mg Pt on Carbon (10% Pt), 199 mg Methoxyphenole and 199 mg Ionol wereplaced in a round bottom flask and heated to reflux. 28 g 1,5-Hexadiene(98%) were added dropwise. Reflux was continued until SiH-band in IRspectum at ˜2100 cm⁻¹ no longer decreased. After workup 32.1 g of ayellow liquid was obtained; (EW) of 284 g/mole.

Example 7 Synthesis of a Crosslinker Component (B) According to 1stExample of Preparation of U.S. Pat. No. 5,086,148

7 mg of hexachloroplatinic acid was introduced into 7.92 g of (20 mMole)bisphenol-A-bisallyloxyethylether and the mixture was stirred for 15minutes at ambient temperature, until the majority of thehexachloroplatinic acid was dissolved. Following this 9.6 g of (40mMole). Tetramethylcyclotetrasiloxane was added drop-wise at ambienttemperature. Within 20 minutes the temperature of the mixture rose to55° C. Stirring was continued until the mixture had cooled to atemperature of 30° C. Stirring was continued for additional 2 hours.Finally, filtration with silica gel removed a small amount of a blackprecipitate and 10 g of compound B was obtained. NMR-spectroscopiccharacterisation showed that the broad multiplett of the allyl groupbetween 5.0 and 6.3 ppm had disappeared. In the infrared spectrum theSiH-group of the product was at 2168 cm⁻¹.

Examples of Use Example of Use 1

Using a standard laboratory mixer a base paste 1 was prepared undervacuum. The following components (weight percent in the mix) were mixedto homogeneity.

Base Paste 1 Component amount = weight-% Component (A) of Example 5 10.0g = 31.8 wt-% Component (B) of Example 7 10.0 g = 31.8 wt.-%Polydimethylsiloxane, trimethylsiloxyterminated  1.0 g = 3.2 wt.-% (η =10 mPa * s) Pyrogenic silica Aerosil R 202  0.5 g = 1.6 wt.-%Cristobalit-Filler (BET = 3 m²/g) 10.0 g = 31.6 wt.-%20 mg of a solution of a platinum-tetramethyl-divinyldisiloxane complexin silicone oil (1.3 weight-% platinum) were added to this paste bystirring. After 1 minute setting reaction started. After 6.5 minutessetting was complete resulting in a hard product. Shore hardness Daccording to DIN 53505 was 73 measured 10 minutes after mixing.

Example of Use 2

A base paste 2 and catalyst paste 2 were prepared using a standardlaboratory mixer under vacuum. The components below were mixed tohomogeneity. Data down below show the components and their amount ingram as well as the resulting weight percent share in the formulation ofthe paste.

Base Paste 2 Component amount = weight-% Component (B) of Example 7 31.7g = 45.4 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated  1.6 g =2.3 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202  0.8 g = 1.1wt.-% Cristobalit-Filler (BET = 3 m²/g) 35.6 g = 51.1 wt.-%

Catalyst Paste 2 Component amount = weight-% Component (A) of Example 28.6 g = 43.0 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated 0.1g = 0.4 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202 1.6 g =11.7 wt.-% Cristobalit-Filler (BET = 3 m²/g) 9.4 g = 43.0 wt.-% Catalyst(C) 0.4 g = 1.9 wt.-%Platinum-Tetramethyl-Divinyldisiloxane-complex in silicone oil (1.3weight-% platinum metal)

Base paste 2 and catalyst paste 2 were filled into standard cartridgesand were mixed by pressing through a static mixing tip at a volume ratioof base:catalyst=4:1. After 25 seconds setting reaction startedindicated by an increase of viscosity and temperature of the mixture.This setting reaction was finished after 1.5 minutes. The result was ahard product having a shore hardness D of 63 measured 24 h after mixing.

Example of Use 3

A base paste 3 and catalyst paste 3 were prepared using a standardlaboratory mixer under vacuum. Components as to be seen down below weremixed to homogeneity. Data down below show the components and theiramount in gram as well as the resulting weight percent share in theformulation of the paste.

Base Paste 3 Component amount = weight-% Component (B) of Example 7 31.7g = 45.5 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated  1.6 g =2.3 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202  0.8 g = 1.1wt.-% Cristobalit-Filler (BET = 3 m²/g) 35.6 g = 51.1 wt.-%

Catalyst Paste 3 Component amount = weight-% Component (A) of Example 531.6 g = 44.3 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated 1.6 g = 2.2 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202  0.8g = 1.1 wt.-% Cristobalit-Filler (BET = 3 m²/g) 35.8 g = 50.2 wt.-%Catalyst (C)  1.6 g = 2.2 wt.-%Platinum-Tetramethyl-Divinyldisiloxane-complex in silicone oil (1.3weight-% platinum metal)

Base paste 3 and catalyst paste 3 were filled into standard cartridgesand were mixed by pressing through a static mixing tipp with a volumeratio of base:catalyst=1:1. After 1.5 minutes setting reaction startedindicated by an increase of viscosity and temperature of the mixture.This setting reaction was finished after 3.5 minutes. The result was ahard product having the following characteristics. Compressive Strength120 MPa Flexural Strength 70 MPa E-Modulus 2390 MPa Tensile Strength 32MPa Impact Strength 9.4 kJ/m² Shore hardness D 77

The mixed paste could be applied directly into set impressions of apatient's mouth based on alginates, addition cured (e.g. Position®Penta®, 3M ESPE AG, Seefeld), or condensation cured silicone impressionmaterials. After setting the material could be easily removed from theimpressions. Because of that the material could be used as a modelmaterial to prepare dental casts from dental impressions and as aproduct for the preparation of provisional crowns and bridges.

Example of Use 4

A base paste 4 and catalyst paste 4 were prepared using a standardlaboratory mixer under vacuum. The components below were mixed tohomogeneity. Data below show the components and their amount in gram aswell as the resulting weight percent share in the formulation of thepaste.

Base Paste 4 Component amount = weight-% Component (B) of Example 7 21.9g = 23.9 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated  1.1 g =1.2 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202  0.5 g = 0.5wt.-% Cristobalit-Filler (BET = 3 m²/g) 68.0 g = 77.4 wt.-%

Catalyst Paste 4 Component amount = weight-% Component (A) of Example 521.3 g = 23.3 wt.-% Polydimethylsiloxane, trimethylsiloxy terminated 1.1 g = 1.2 wt.-% (η = 10 mPa * s) Pyrogenic silica Aerosil R 202  0.5g = 0.5 wt.-% Cristobalit-Filler (BET = 3 m²/g) 68.0 g = 74.5 wt.-%Catalyst (C)  0.4 g = 0.5 wt.-%Platinum-Tetramethyl-Divinyldisiloxane-complex in silicone oil (1.3weight-% platinum metal)

Base paste 4 and catalyst paste 4 were mixed at a volume ratio ofbase:catalyst=1:1. After 2.5 minutes setting reaction started and wasfinished after 9 minutes. The result was a hard product having thefollowing characteristics. Compressive Strength 114 MPa  FlexuralStrength 64 MPa E-Modulus 3562 MPa  Tensile Strength 30 MPa Shorehardness D 84All cured compositions of the inventive examples showed a high Shorehardness D and usually a high E-modulus. The components of thecomposition could be mixed easily. The cured composition did not show asmear layer.

1. Curable composition comprising: addition curable silicone component(A) having a linear siloxane backbone, and at least one unsaturated,non-activated side group pendant from a Si atom or atoms in thebackbone, component (A) having an equivalent weight (EW) in the range ofabout 68 to about 1000 g/mole; crosslinker component (B) comprising atleast 2 SiH groups; catalyst component (C); and filler component (D),wherein the total number of carbon-carbon double bonds in component (A)is at least 3, and the unsaturated, non-activated side group does notcomprise a —O—Si—CH═CH₂ moiety.
 2. Composition according to claim 1,wherein component (A) has a viscosity less than or equal to about 50Pa*s.
 3. Composition according to claim 1, wherein component (A) has amolecular weight less than or equal to about 100,000 gmole⁻¹. 4.Composition according to claim 1, wherein the composition, after curing,has a shore hardness D of at least
 55. 5. Composition according to claim1, wherein the composition, after curing, has an E-modulus above about1000 Mpa.
 6. Composition according to claim 1, wherein the composition,after curing, has an impact strength greater than about 1 kJ/m^(2.) 7.Composition according to claim 1, wherein the composition, after curing,has a flexural strength greater than about 60 Mpa.
 8. Compositionaccording to claim 1, wherein the composition, after curing, has acompressive strength greater than about 100 MPa.
 9. Compositionaccording to claim 1, wherein crosslinker component (B) has a viscositygreater than about 50 mPa*s.
 10. Composition according to claim 1further comprising inhibitor component (E).
 11. Composition according toclaim 1 further comprising at least one component (F) selected from thegroup consisting of modifiers, dyes, pigments, thixotropic agents, flowimprovers, polymeric thickeners, surfactants, odorous substances,diluting agents or flavourings.
 12. Composition according to claim 1,wherein: component (A) is present in an amount of at least about 1wt.-%; crosslinker component (B) is present in an amount of at leastabout 1 wt.-%; catalyst component (C) is present in an amount of atleast about 0.00005 wt.-%; and filler component (D) is present in anamount of at least about 4 wt.-% with respect to the total compositionweight.
 13. Composition according to claim 1, wherein component (A) isobtainable via a reaction comprising the steps of reacting a compoundaccording to formula (1)[A(B)_(b)]_(a)C¹¹   (1) wherein: A=linear or branched, terminallyunsaturated, aliphatic residue, wherein the unsaturation is a C—C doublebond not activated by a conjugated carbonyl group; B=O, (O═)C—O,O—C(═O), O—C(═O)—O, NH, S; C¹¹=H, aliphatic, cycloaliphatic, aromaticorganic or silicon organic residue comprising 1 to 50, carbon atoms, andadditionally, up to 6 hetero atoms which can also be part of a ringsystem; a=2, 3, 4, 5, 6, 7, 8, 9 or 10; and b=0 or 1 with a compoundaccording to formula (2)

wherein R1=alkyl, aryl or alkaryl each comprising 1 to 20 carbon atoms,wherein one or more H atoms can be substituted by halogen atoms or alkylgroups; R2=H, R1 or alkenyl with 1 to 10 carbon atoms; n=0 to 500, andm=0 to
 500. 14. Composition according to claim 13, wherein n is 0 to 100and m is 0 to
 100. 15. Composition according to claim 1, whereincomponent (A) is represented by formula (3):

wherein: R1=alkyl, aryl or alkaryl each comprising 1 to 20 carbon atoms,wherein at least one of the carbon atoms can be substituted with ahalogen atom or alkyl group; R2=is either equal to R1 or, where p is 0,R4; R3=alkyl, aryl or alkaryl group comprising 1 to 20 carbon atoms,wherein one or more of the H atoms can be substituted by a halogen atom;R4=linear or branched, terminally unsaturated aliphatic, cycloaliphaticor aromatic organic or silicon organic residue moiety having (a-1)ethylenic unsaturations, and wherein such unsaturations arecarbon-carbon double bonds not activated by a conjugated carbonyl group,wherein the moiety comprises 1 to 50 carbon atoms and additionally up to6 oxygen atoms which can also be part of a ring system; o=0 to 12; m=0to 50; p=0 to 500; and a=2, 3, 4, 5, 6, 7, 8, 9 or
 10. 16. A coating ofthe composition according to claim 1 on a tooth.
 17. A method oftreating a tooth comprising, application of the composition according toclaim 1 to a tooth and curing the coating to the desired properties. 18.A dental material comprising the composition of claim
 1. 19. The dentalmaterial according to claim 18 wherein the dental material is selectedfrom the group consisting of filling material, cement, provisional crownand bridge material, or bite registration material.
 20. Kit of parts,comprising a base part (I) and a catalyst part (II), wherein the basepart (I) comprises: addition curable silicone component (A) having alinear siloxane backbone, and at least one unsaturated, non-activatedside group pendant from a Si atom or atoms in the backbone, component(A) having an equivalent weight (EW) in the range of 68 to 1000 g/mole;and crosslinker component (B) comprising at least 2 SiH groups; whereinthe total number of carbon-carbon double bonds in component (A) is atleast 3 and wherein the unsaturated, non-activated side group does notcomprise a —O—Si—CH═CH₂ moiety, and the catalyst part (II) comprisescatalyst component (C).